Bathing Water Samples Research Articles

Correlation between bacterial microbiome and Legionella species in water from public bath facilities by 16S rRNA gene amplicon sequencing.

Public bath facilities are major sources of sporadic cases and outbreaks of Legionella infections. Recently, 16S rRNA gene amplicon sequencing has been used to analyze bacterial characteristics in various water samples from both artificial and natural environments, with a particular focus on Legionella bacterial species. However, the relationship between the bacterial community and Legionella species in the water from public bath facilities remains unclear. In terms of hygiene management, it is important to reduce the growth of Legionella species by disinfecting the water in public bath facilities. Our findings contribute to the establishment of appropriate hygiene management practices and provide a basis for understanding the potential health effects of using bath and shower water available in public bath facilities.

Modelling Bathing Water Quality Using Official Monitoring Data

Predictive models of bathing water quality are a useful support to traditional monitoring and provide timely and adequate information for the protection of public health. When developing models, it is critical to select an appropriate model type and appropriate metrics to reduce errors so that the predicted outcome is reliable. It is usually necessary to conduct intensive sampling to collect a sufficient amount of data. This paper presents the process of developing a predictive model in Kaštela Bay (Adriatic Sea) using only data from regular (official) bathing water quality monitoring collected during five bathing seasons. The predictive modelling process, which included data preprocessing, model training, and model tuning, showed no silver bullet model and selected two model types that met the specified requirements: a neural network (ANN) for Escherichia coli and a random forest (RF) for intestinal enterococci. The different model types are probably the result of the different persistence of two indicator bacteria to the effects of marine environmental factors and consequently the different die-off rates. By combining these two models, the bathing water samples were classified with acceptable performances, an informedness of 71.7%, an F-score of 47.1%, and an overall accuracy of 80.6%.

Morphological transformation assisted switchable deep eutectic solvents combined with HPLC-DAD for the detection of six UV-filters in surface and bathing waters

Detection of ultraviolet (UV) filters in environmental matrices has aroused great interest; however, most relevant analytic approaches lack efficiency and convenience. Herein, a ‘green’ fatty acid-based deep eutectic solvent (FA-DES), with both the ‘switchability’ (between hydrophobicity and hydrophilicity) and proper melting points for solidification was synthesized to preconcentrate/extract six UV filters in river, lake, sea, and bathing water samples. The switchable FA-DES acts as both the extractant and disperser, thereby reducing the overall solvent consumption. Strong electrolytes and effervescence produced in-situ during ‘switch’ propelled the lipophilic UV filters salting out and mass-transferring from aqueous phase to DES phase. Quick solidification of FA-DES after extraction realized thorough phase separation with less analyte loss and transfer errors. Overall, these advantageous characteristics are conductive to the superior extraction performance of FA-DES for UV-filters. Synthesizing conditions of the selected DES and extraction parameters were optimized by central composite design (CCD) and univariate analysis. Under the optimum conditions, the limits of detection (LOD) and recovery for six UV-filters in real samples were in the range of 0.021–0.336 μg/L and 86.2–116.6%, respectively. Overall, the proposed methodology is eco-friendly, efficient, convenient and cost-effective, and thus has promising prospect for quantitative analysis of diverse UV-filters in various environmental aqueous samples. For instance, the method can be utilized to monitor the concentration level of UV-filters in swimming pools, lidos, and recreational water.

Investigations of Detergents and Metal Components for Supporting the Effective Treatment of Greywater

Abstract The aim of our research was to investigate the detergent content and several micro and macro elements in greywater samples, a necessary step in determining the water quality for the further reuse of the greywater. We determined the anionic detergent content of synthetic greywater with a two-phased titration method prepared in laboratory conditions. The current study leads to a new suggestion for a more accurate and reliable titrimetric method for determination of anionic detergent content of synthetic greywater samples. Following these investigations, we also examined the metal content of synthetic bath water. We wanted to highlight how detergents in greywater influence the micro and macro element content of the given synthetic bath water samples.

Assessment of bathing water quality with an E. coli immunosensor

ABSTRACT Escherichia coli is a Gram-negative, facultative anaerobic, rod-shaped coliform bacterium which is widely used as an indicator of biological safety of water. Currently, ‘gold’ standard for the detection of E. coli (and other pathogens) are microbiological culture-based tests. Microbiological tests are very robust for the detection of live pathogens however it can take several days to get the results. A prospective option for the detection of E. coli in recreational waters in addition to the genetic PCR analyses can be an immunobiosensor, allowing to detect E. coli in 20 min and to issue timely warnings of the safety of water. To compare different methods – microbiological culturing, quantitative PCR analysis and antibody-based immunobiosensor for the analysis of bathing water samples from a popular urban beach Anne Canal in Tartu, Estonia were used. The median value of biosensor results for E. coliwas considerably higher than the results of microbiological cultivation and qPCR: for 40 times, and 4 times, respectively. In addition, the biosensor results were in significant correlation with the number of total coliforms. Considering the current requirements for the biological safety of bathing water, we propose that the indicative safety threshold for bathing water usingimmunosensor analyses is in the range 4 × 103–4 x 104 E. coli cells/100 mL.

Evaluation of Legiolert for Quantification of Legionella pneumophila from Bath Water Samples.

Testing for Legionella spp. in public bath water samples is regulated in Japan. In this study, we used a total of 132 public bath water samples to compare the performance of Legiolert® and the conventional plate culture method for the enumeration of Legionella pneumophila. When Legiolert and plate culturing were performed at the same detection limit, L. pneumophila was detected in 26.5% of 132 samples by Legiolert, while 12.9% contained Legionella spp. (11.4% contained L. pneumophila) based on the plate culture method. Moreover, results of 83.3% of the total samples were consistent between the two methods, meaning that they were both positive or both negative. In this study, we demonstrated that Legiolert is a simpler and more effective method of monitoring for L. pneumophila in bath water samples.

Monitoring Tangier (Morocco) coastal waters for As, Fe and P concentrations using ESA Sentinels-2 and 3 data: An exploratory study

An exploratory study is presented to investigate human activities pollution in the coastal waters of a popular tourist destination in the west coast of Tangier, Morocco. A series of bathing water samples were examined for arsenic (As), iron (Fe) and phosphorus (P) concentrations in the western coastal waters of Tangier. Additionally, quasi-simultaneous satellite images from Sentinels-2 and 3 were processed to retrieve water leaving reflectances in the same locations. The bathing water samples showed high concentrations of As, P and Fe in the Boukhalef River mouth and in two nearby beaches; Jbila and Sidikacem, which appeared closely correlated with Sentinel-3 reflectances at bands 6 (560 nm) and 7 (620 nm). Since algorithms for Chlorophyll-a and Total Suspended Matter Concentrations rely on these wavelengths, they too were found to be closely related to high As, Fe and P concentrations. Therefore, caution must be taken when analysing these level-2 products in close proximity to the Boukhalef River mouth, since results may be biased due to the presence of significant As, Fe and P concentrations. In this case, Sentinel data proved to be a potentially useful tool with prospects to be used for monitoring environmental hazardous substances such as metals (e.g. As and Fe) spatial distributions in the west coast of Tangier, Morocco.

Enteric viruses, somatic coliphages and Vibrio species in marine bathing and non-bathing waters in Italy.

Microbial safety of recreational waters is a significant public health issue. In this study we assessed the occurrence and quantity of enteric viruses in bathing and non-bathing waters in Italy, in parallel with microbial faecal indicators, somatic coliphages and Vibrio spp. Enteric viruses (aichivirus, norovirus and enterovirus) were detected in 55% of bathing water samples, including samples with bacterial indicator concentrations compliant with the European bathing water Directive. Aichivirus was the most frequent and abundant virus. Adenovirus was detected only in non-bathing waters. Somatic coliphages were identified in 50% bathing water samples, 80% of which showed simultaneous presence of viruses. Vibrio species were ubiquitous, with 9 species identified, including potential pathogens (V. cholerae, V. parahaemoylticus and V. vulnificus). This is the first study showing the occurrence and high concentration of Aichivirus in bathing waters and provides original information, useful in view of a future revision of the European Directive.

Is TBX agar a suitable medium for monitoring Escherichia coli in bathing water using the membrane filtration method?

The use of a suitable method for the enumeration of indicator microorganisms is of crucial importance for reliable monitoring and assessment of the quality of bathing waters. Among other characteristics, the method should be selective enough and ensure acceptable relative recovery of target microorganisms. This study presents the basic parameters, relative recovery and categorical performance characteristics of Tryptone Bile X-glucuronide (TBX) agar for Escherichia coli (E. coli) enumeration in bathing water samples using the membrane filtration method.The results of the relative recovery study, in which TBX agar was compared against temperature-modified ISO 9308-1:2014, showed that in order to achieve a satisfactory relative recovery of E. coli with TBX agar at 44 ± 0.5°C, the resuscitation period on a non-selective medium (Minerals Modified Glutamate Agar, MMGA) at 36 ± 2°C is crucial. Incubation on a double-layer MMGA/TBX medium with a 6-h resuscitation period and alternating incubation on single-layer MMGA and TBX agar with a 4-h resuscitation period resulted in acceptable and very similar relative recovery. The achieved performance characteristics of the tested medium, double-layer MMGA/TBX agar, are acceptable. The selectivity was matrix-dependent and was 60.6% for inland and 69.9% for coastal waters. No significant effect of the resuscitation period on selectivity was recorded. Finally, the results showed that when the resuscitation period on a non-selective medium is included, TBX agar is a suitable medium for E. coli enumeration in bathing water samples using the membrane filtration method and that its use, theoretically, would not have negative effects on the assessment of bathing water quality.

Exposure to and colonisation by antibiotic-resistant E. coli in UK coastal water users: Environmental surveillance, exposure assessment, and epidemiological study (Beach Bum Survey)

BackgroundAntibiotic-resistant bacteria (ARB) present a global public health problem. With numbers of community-acquired resistant infections increasing, understanding the mechanisms by which people are exposed to and colonised by ARB can help inform effective strategies to prevent their spread. The role natural environments play in this is poorly understood. This is the first study to combine surveillance of ARB in bathing waters, human exposure estimates and association between exposure and colonisation by ARB in water users. Methods97 bathing water samples from England and Wales were analysed for the proportion of E. coli harbouring blaCTX-M. These data were used to estimate the likelihood of water users ingesting blaCTX-M-bearing E. coli. Having identified surfers as being at risk of exposure to ARB, a cross-sectional study was conducted. Regular surfers and non-surfers were recruited to assess whether there is an association between surfing and gut colonisation by blaCTX-M-bearing E. coli. Results11 of 97 bathing waters sampled were found to contain blaCTX-M-bearing E. coli. While the percentage of blaCTX-M-bearing E. coli in bathing waters was low (0.07%), water users are at risk of ingesting these ARB. It is estimated that over 2.5 million water sports sessions occurred in 2015 resulting in the ingestion of at least one blaCTX-M-bearing E. coli. In the epidemiological survey, 9/143 (6.3%) surfers were colonised by blaCTX-M-bearing E. coli, as compared to 2/130 (1.5%) of non-surfers (risk ratio=4.09, 95% CI 1.02 to 16.4, p=0.046). ConclusionsSurfers are at risk of exposure to and colonisation by clinically important antibiotic-resistant E. coli in coastal waters. Further research must be done on the role natural environments play in the transmission of ARB.

Escherichia coli in marine water: Comparison of methods for the assessment of recreational bathing water samples

Bathing Water Directive (2006/7/EC) specifies two reference methods for Escherichia coli detection: ISO 9308-1 and 9308-3. The revised ISO 9308-1 is recommended only for waters with a low bacterial background flora. Considering the extended time needed for analysis and, generally, the lack of experience in using ISO 9308-3 in the Mediterranean, the suitability of ISO 9308-1 for the examination of E. coli in bathing water was evaluated. The present study was aimed at a comparison of data obtained by the reference method in seawater samples (110 beaches, N=477) with data received from six alternative methods. Results show that recently used TSA/TBA method may overestimate E. coli numbers in marine waters. The temperature modified ISO 9308-1 (44°C) did not significantly alter the results, but outperformed the antibiotic supplemented agar at reducing non-E. coli bacteria on the plates, allowing the use of the respective method for monitoring coastal water.

Determination of fourteen UV filters in bathing water by headspace solid-phase microextraction and gas chromatography-tandem mass spectrometry

A headspace SPME-GC-MS/MS method for the analysis of 14 UV filters in different types of bathing water samples has been developed.

Investigation of Legionella Contamination in Bath Water Samples by Culture, Amoebic Co-Culture, and Real-Time Quantitative PCR Methods.

We investigated Legionella contamination in bath water samples, collected from 68 bathing facilities in Japan, by culture, culture with amoebic co-culture, real-time quantitative PCR (qPCR), and real-time qPCR with amoebic co-culture. Using the conventional culture method, Legionella pneumophila was detected in 11 samples (11/68, 16.2%). Contrary to our expectation, the culture method with the amoebic co-culture technique did not increase the detection rate of Legionella (4/68, 5.9%). In contrast, a combination of the amoebic co-culture technique followed by qPCR successfully increased the detection rate (57/68, 83.8%) compared with real-time qPCR alone (46/68, 67.6%). Using real-time qPCR after culture with amoebic co-culture, more than 10-fold higher bacterial numbers were observed in 30 samples (30/68, 44.1%) compared with the same samples without co-culture. On the other hand, higher bacterial numbers were not observed after propagation by amoebae in 32 samples (32/68, 47.1%). Legionella was not detected in the remaining six samples (6/68, 8.8%), irrespective of the method. These results suggest that application of the amoebic co-culture technique prior to real-time qPCR may be useful for the sensitive detection of Legionella from bath water samples. Furthermore, a combination of amoebic co-culture and real-time qPCR might be useful to detect viable and virulent Legionella because their ability to invade and multiply within free-living amoebae is considered to correlate with their pathogenicity for humans. This is the first report evaluating the efficacy of the amoebic co-culture technique for detecting Legionella in bath water samples.

Determination of ultraviolet filters in bathing waters by stir bar sorptive–dispersive microextraction coupled to thermal desorption–gas chromatography–mass spectrometry

In this work, a new approach that combines the advantages of stir bar sorptive extraction (SBSE) and dispersive solid phase extraction (DSPE), i.e. stir bar sorptive–dispersive microextraction (SBSDµE), is employed as enrichment and clean-up technique for the sensitive determination of eight lipophilic UV filters in water samples. The extraction is accomplished using a neodymium stir bar magnetically coated with oleic acid-coated cobalt ferrite magnetic nanoparticles (MNPs) as sorbent material, which are detached and dispersed into the solution at high stirring rate. When stirring is stopped, MNPs are magnetically retrieved onto the stir bar, which is subjected to thermal desorption (TD) to release the analytes into the gas chromatography–mass spectrometry (GC–MS) system. The SBSDµE approach allows for lower extraction time than SBSE and easier post-extraction treatment than DSPE, while TD allows for an effective and solvent-free injection of the entire quantity of desorbed analytes into GC–MS, and thus achieving a high sensitivity. The main parameters involved in TD, as well as the extraction time, were evaluated. Under the optimized conditions, the method was successfully validated showing good linearity, limits of detection and quantification in the low ngL−1 range and good intra- and inter-day repeatability (RSD<12%). This accurate and sensitive analytical method was applied to the determination of trace amounts of UV filters in three bathing water samples (river, sea and swimming pool) with satisfactory relative recovery values (80–116%).

Comparison of Colilert-18 with miniaturised most probable number method for monitoring of Escherichia coli in bathing water

The purpose of this equivalence study was to compare an alternative method, Colilert-18 Quanti-Tray (ISO 9308-2) with the European bathing water directive (2006/7/EC) reference method, the miniaturised most probable number (MMPN) method (ISO 9308-3), for the analysis of Escherichia coli. Six laboratories analysed a total of 263 bathing water samples in Finland. The comparison was carried out according to ISO 17994:2004. The recovery of E. coli using the Colilert-18 method was 7.0% and 8.6% lower than that of the MMPN method after 48 hours and 72 hours of incubation, respectively. The confirmation rate of presumptive E. coli-positive wells in the Colilert-18 and MMPN methods was high (97.8% and 98.0%, respectively). However, the testing of presumptive E. coli-negative but coliform bacteria-positive (yellow but not fluorescent) Colilert-18 wells revealed 7.3% false negative results. There were more false negatives in the naturally contaminated waters than in the samples spiked with waste water. The difference between the recovery of Colilert-18 and the MMPN method was considered not significant, and subsequently the methods are considered as equivalent for bathing water quality monitoring in Finland. Future bathing water method equivalence verification studies may use the data reported herein. The laboratories should make sure that any wells showing even minor fluorescence will be determined as positive for E. coli.

Detection of Legionella species in environmental water by the quantitative PCR method in combination with ethidium monoazide treatment.

We detected Legionella species in 111 bath water samples and 95 cooling tower water samples by using a combination of conventional plate culture, quantitative polymerase chain reaction (qPCR) and qPCR combined with ethidium monoazide treatment (EMA-qPCR) methods. In the case of bath water samples, Legionella spp. were detected in 30 samples by plate culture, in 85 samples by qPCR, and in 49 samples by EMA-qPCR. Of 81 samples determined to be Legionella-negative by plate culture, 56 and 23 samples were positive by qPCR and EMA-qPCR, respectively. Therefore, EMA treatment decreased the number of Legionella-positive bath water samples detected by qPCR. In contrast, EMA treatment had no effect on cooling tower water samples. We therefore expect that EMA-qPCR is a useful method for the rapid detection of viable Legionella spp. from bath water samples.

Molecular characterization of viable Legionella spp. in cooling tower water samples by combined use of ethidium monoazide and PCR.

Viable Legionella spp. in environmental water samples were characterized phylogenetically by a clone library analysis combining the use of ethidium monoazide and quantitative PCR. To examine the diversity of Legionella spp., six cooling tower water samples and three bath water samples were collected and analyzed. A total of 617 clones were analyzed for their 16S rRNA gene sequences and classified into 99 operational taxonomic units (OTUs). The majority of OTUs were not clustered with currently described Legionella spp., suggesting the wide diversity of not-yet-cultured Legionella groups harbored in cooling tower water environments.

Bath water contamination with Legionella and nontuberculous mycobacteria in 24-hour home baths, hot springs, and public bathhouses of Nagano Prefecture, Japan.

Bath water samples were collected from 116 hot springs, 197 public bathhouses, and 38 24-hour home baths in Nagano Prefecture, Japan, during the period of April 2009 to November 2011, for determining the presence and extent of contamination with Legionella and nontuberculous mycobacteria. Cultures positive for Legionella were observed in 123 of the 3,314 bath water samples examined. The distribution and abundance of Legionella and/or combined contamination with Legionella and nontuberculous mycobacteria were investigated to clarify the contamination levels. The abundance of Legionella was demonstrated to correlate considerably with the levels of combined contamination with Legionella and nontuberculous mycobacteria. Legionella spp. were obtained from 61% of the water samples from 24-hour home baths, but only from 3% of the samples from public bathhouses and hot springs. This is despite the fact that a few outbreaks of Legionnaires' disease in Nagano Prefecture as well as other regions of Japan have been traced to bath water contamination. The comparatively higher rate of contamination of the 24-hour home baths is a matter of concern. It is therefore advisable to routinely implement good maintenance of the water basins, particularly of the 24-hour home baths.

Pulsed-Field Gel Electrophoresis (PFGE) Pattern Analysis and Chlorine-Resistance of Legionella pneumophila Isolated from Hot Spring Water Samples

For a microbial ecological analysis, 20 strains of Legionella pneumophila isolated from both unchlorinated Noyu (unattended natural hot spring) samples and chlorinated hot spring bath water samples collected throughout Japan were subjected to a clustering analysis on the basis of a Pulsed-Field Gel Electrophoresis (PFGE) pattern analysis. The PFGE patterns obtained from 19 strains of L. pneumophila after digestion with SfiI were used to divide the strains into two groups (Groups A and B), although the similarity level was very low among the groups. Group A consisted of 8 strains, and all of these strains were isolated from hot spring bath water samples. Group B consisted of 11 strains, and all but two of these strains were isolated from Noyu samples. The chlorine resistance (99.9% CT values) of these isolates was experimentally confirmed, and we attempted to define the relationship between chlorine resistance and the geno-cluster. The average CT value of group A (8 strains from hot spring bath water) was 0.49 mg･min/l and the average of group B (9 strains from Noyu samples) was 0.29 mg･min/l. No remarkable differences in the CT values for the groups were found. A chlorine-sensitive Noyu strain (0.14 mg･min/l) and a chlorine-resistant strain (0.62 mg･min/l) from hot spring bath water were then compared to identify any differences in their lipid composition. There was no notable difference in the ratio of saturated to unsaturated fatty acids between the chlorine-sensitive and chlorine-resistant bacteria. However, the chlorine-sensitive and chlorine-resistant bacteria demonstrated differences in the relative percentages of cell wall and cell membrane fatty acids.

Occurrence of thermotolerant Campylobacter spp. and adenoviruses in Finnish bathing waters and purified sewage effluents

A total of 50 Finnish bathing water samples and 34 sewage effluent samples originating from 17 locations were studied in the summers of 2006 and 2007. Campylobacter were present in 58% and adenoviruses in 12% of all bathing water samples; 53% of all sewage effluent samples were positive for Campylobacter spp. and 59% for adenoviruses. C. jejuni was the most common Campylobacter species found and human adenovirus serotype 41 was the most common identified adenovirus type. Bathing water temperature displayed a significant negative relationship with the occurrence of Campylobacter. One location had identical pulsed-field gel electrophoresis patterns of C. coli isolates in the bathing water and in sewage effluent, suggesting that sewage effluent was the source of C. coli at this bathing site. The counts of faecal indicator bacteria were not able to predict the presence of Campylobacter spp. or adenoviruses in the bathing waters. Thus the observed common presence of these pathogens in Finnish sewage effluents and bathing waters may represent a public health risk. The low water temperature in Finland may enhance the prevalence of Campylobacter in bathing waters. More attention needs to be paid to minimizing the concentrations of intestinal pathogens in bathing waters.